1. Field of the Invention
The present invention relates generally to the field of aquaculture and fish farming, and is more particularly directed to a composition and novel method of using the same to promote accelerated growth and enhanced feed conversion efficiency in fish.
2. Description of the Related Art
The production of marine and freshwater fish for food and other commercial or recreational purposes is a fast growing industry in the United States and throughout the world. In order to meet product demands and to sustain high crop yields, aquaculturists have long strived to develop methods for promoting and enhancing growth in fish. To this end, water quality and disease management techniques have been used and continue to be developed to provide a stress free fish farm environment that is conducive to growth. In addition, nutritional studies have provided insight as to the type and amount of nutrients required by various species of fish to reach their maximum growth potential.
Prompted in part by the noted successes of the animal husbandry industry, aquaculturists have also investigated various methods that are known to stimulate accelerated tissue growth, improve feed conversion efficiency and increase lean to fat ratios in livestock. For example, a positive growth response has been noted when specially prepared polypeptide sequences that stimulate the release of growth hormone (GH) are administered to livestock. Polypeptides have now been developed to similarly stimulate the release of pituitary growth hormone in fish. U.S. Pat. No. 4,843,064 to Vaughan et al. This method has reportedly been useful in accelerating growth in fish, but there are some practical drawbacks to its use in aquaculture. Most notably, GH stimulating polypeptides are generally required to be administered to the fish by parenteral injection or implantation, because digestive enzymes in the digestive tract are expected to cleave and destroy the polypeptide chain if taken orally. Although parenteral application may be feasible for breeding purposes to promote rapid growth of selected stock, it is not generally considered a viable or cost effective method of growth promotion for commercial fishery operations.
Aquaculturists have also investigated the administration of steroids to fish as a method of enhancing growth. Both androgenic and estrogenic compounds have been used extensively and with great success in the animal husbandry industry, however the results in fish have been varied to date. For instance, androgenic compounds, and particularly the androgen methyl-testosterone has generally exhibited a positive growth promoting effect in fish. See, Donaldson, E. M., U. H. M. Fagerlund, D. A. Higgs, and J. R. McBride, 1979. "Hormonal Enhancement of Growth" pp. 455-578. in W. S. Hoar D. J. Randall and J. R. Brett [ed] Fish Physiology, Volume 8, Academic Press, New York, N.Y. Yet evidence linking methyltestosterone to cancer has reduced its desirability for use in fish farming, most notably due to concerns regarding the effect that any remaining residue in consumable fish might have on humans. The administration of estrogenic compounds to fish, on the other hand, has rarely shown an enhanced growth effect in fish and has even been linked to inhibiting growth in some species by negatively effecting fish thyroid levels. See, Malison J. A., C. D. Best, T. B. Kayes, C. H. Amundson, and B. C. Wentworth. 1985. "Hormonal Growth Promotion and Evidence for a Size-Related Difference in Response to Estradial-17 in Yellow Perch. (Perca flavescens)". Can. J. Fish. Aquat. Sci. 42:1627-1633.
In view of the foregoing, it is a primary object of the present invention to provide a composition for promoting growth in fish that is convenient and cost effective for use in commercial fishery operations.
It is also an object of the present invention to provide a composition and method of use for accelerating the rate of weight gain in fish.
A related object of the present invention is to provide a composition and method of use for increasing the lean to fat ratio in fish.
Another object of the present invention is to provide a growth promoting composition that can be conveniently administered to fish orally.
A further object of the present invention is to provide a composition that is effective in promoting growth in fish when added as a supplement to fish feed.
Another object of the present invention is to provide a feed formulation that effectively promotes accelerated growth in fish.
Yet another object of the present invention is to provide a composition and method of use for promoting growth in juvenile Barramundi fish (Lares calcerifer).
It is a further object of the present invention to provide a growth promoting composition and method of using the same that is relatively safe for use with consumable fish.